I happen to see the same behaviour here. However, I found that using gdebi-gtk instead of gdebi-kde works fine!
Cheers Holger -- ============================================================ Created with Sylpheed 3.5.0 under D E B I A N L I N U X 8 . 0 " J E S S I E " . Registered Linux User #311290 - https://linuxcounter.net/ ============================================================